One easy way to tell if you're drinking beer from a dirty glass

The pub at the end of my block has a ton going for it. It boasts
a huge variety of craft beers, a beautiful patio, and a killer
Monday night trivia.

But every time I order a fancy brew at a great bar like this, I
wonder, is their glassware clean?

Luckily, there's a super easy way to tell. If the inside of your
pint glass is dirty, one main thing will happen: Streams of
bubbles will flow from the walls of your glass.

I know, it sounds weird because — unless your beer is flat —
there are going to be bubbles dancing all over the place. But if
the fizz is originating from the inside walls, your cup
probably has some gunk in it.

This happens because the tiny layers of grime are creating rough
spots on the glass that agitate the beer. These are called
"nucleation points," which provide a place for the dissolved gas
in your beer — usually carbon dioxide — to latch on and form
bubbles. This makes your beer fizzy.

The physical process is similar to what happens when you
drop a Mentos tablet into a can of Diet Coke. The dissolved
gas in the soda gives the drink its bubbles. The liquid is
bottled under pressure to keep the bubbles in, and when you open
the can or bottle, those bubbles start to make their way out of
the liquid, creating the beer's distinctive fizz.

While the gas will create bubbles naturally, you can speed along
this process by giving the bubbles something to latch on to. An
object with rough ridges or a bumpy surface — the Mentos, for
example, or grime on a glass — can catalyze bubble-making.

In the classic Mentos and Diet Coke experiment, the mint drops to
the bottom of the soda and forms so many bubbles that it creates
intense pressure. Those bubbles have nowhere to go but up,
causing an eruption.

Nucleation is generally a good thing when it comes to beers. More
and more, brewers and glass manufacturers designing
glasses with lasered etchings on the bottom of the cup to
agitate the beer and promote fizziness and a frothy head.

But if this fizziness is coming from a dirty glass, then you
should definitely bring it back and demand a new one. There's no
shame in becoming even more of a beer snob than you already are.